This invention relates to electronic rotary switches. Such switches are used in a great variety of applications to control or adjust input or outputs. Two familiar examples are the temperature control and blower fan motor control in an automotive vehicle.
Numerous designs of electronic rotary switches are known. A potentiometer is a well known device for controlling the amount of voltage potential in a circuit. With the advent of microprocessors and digital control of many components, encoders have been widely adopted as a means to control various systems, including electronics. Switches configured as potentiometers and encoders are used in an enormous variety of applications. Any application involving an electrical control panel will commonly have a potentiometer or an encoder or sometimes both for controlling things such as temperature, motor speed, frequency, timing, pressure, or mode of operation. The signals produced by the potentiometer or encoder are commonly sensed by an integrated circuit attached to a printed circuit board (PCB), also known as a printed wiring board or PWB. Depending on the application, the integrated circuit could be a microprocessor capable of processing a substantial number of inputs and controlling a variety of parameters.
For encoders or potentiometers adapted for use in an automotive vehicle interior, such as climate control switches, the cost of an encoder or potentiometer is typically on the order of $3-$4, not including the PCB or the microprocessor. A lower cost rotary switch that reliably replicates the functions of a potentiometer or encoder or mode control selector is desirable.